Six PHS supported investigators are requesting a cell sorter FACStar Plus) to enhance current research projects and permit the development of these programs into area that cannot be currently examined. The principal investigator and co-principal investigator have considerable experience with flow cytometry and will work together in the supervision of technical personnel and administrative and scientific oversight of the cell sorter. An internal advisory committee will monitor the use of the cell sorter and help in scheduling, training, and education of the user group. All projects require the analysis capability of the instrument for cell surface or internal antigen expression and quantitation, cell cycle analysis, DNA content determination, ion flux and mobilization, as well as mobilization of lipids and their influence on biological processes. Cell sorting capabilities will be utilized to examine the functional capabilities of purified cells following or prior to virus infection or transfection (hepatitis B virus or HIV) or exposure to biologically active natural or synthetic compounds. The use of cell sorting in cloning of cells with unique characteristics is an important advance to be taken advantage of in several projects. Furthermore, the automatic sample transfer accessory will permit investigators to isolate, for example, hybridomas present in low frequency (10-3 or less) secreting antibodies to receptors that are highly conserved between species and thus poorly immunogenic. The need for a cell sorter is great and Tulane Medical School has committed funds for the installation, continued maintenance, and technical support of the cell sorter. The Medical School does not now have such an instrument, which in the long term will serve to enhance the productivity and capabilities of numerous research projects.